Patent document 1 shows a known turning behavior control system of such a type.
The gist of this turning behavior control system is as follows. When a driver's steering speed is rapid beyond a preset speed, the control system decreases the vehicle speed to a target vehicle speed (bringing the deceleration to a target deceleration) by decreasing the target vehicle speed (increasing the target deceleration), and thereby prevents the vehicle turning behavior due to the steering from exceeding a limit behavior corresponding to the steering speed.
In case of a rapid steering to change lanes for emergency avoidance, for example, the turning behavior control system of such a type can limit the vehicle turning behavior determined in connection with the steering and the vehicle speed, to the limit behavior dependent on the steering speed, by decreasing the vehicle speed (increasing the deceleration). Consequently, the control system can prevent a great turning behavior of the vehicle even if a deceleration by the driver is deficient or delayed, so that the control system is advantageous for safety.